Java 8 Features

Objective

The objective of this module is to gain hands-on experience with the following Java 8 features:

1. Functional Programming
2. Lambda Expressions
3. Streams
4. Optional Class

---

Working with Java 8 Features

Objectives

1. Understand and implement Lambda Expressions in Java.
2. Understand and implement Streams for processing large datasets.
3. Work with the Optional Class.

Problem Statement

Process the list of Employees based on the following business requirements:

• Display each employee profile.
• Find an employee based on ID and display their profile. If no employee exists with the specified ID, throw EmployeeNotFoundException.
• Add a new employee to the list. If the employee already exists, throw EmployeeAlreadyExistsException.
• Group all employees based on their department, using their designation to filter since there is no department property.

Tasks

1. Remove Duplicates: Remove duplicate employee objects from employeeList added in the previous Lab.

2. Create Exception Classes:

   • Under the com.digisafari.exception package, create EmployeeNotFoundException and EmployeeAlreadyExistsException classes.
   • Use argument constructors for both these Exception classes with the appropriate exception message.

3. Create EmployeeService Interface:

   • Define the following methods:

     public List<Employee> getEmployees();
     public Employee findEmployeeById(int empId) throws EmployeeNotFoundException;
     public Employee addEmployee(Employee employee) throws EmployeeAlreadyExistsException;
     public Employee updateEmployee(Employee employee) throws EmployeeNotFoundException;
     public boolean deleteEmployee(int empId) throws EmployeeNotFoundException;

4. Implement EmployeeService Interface:

   • Create a class named EmployeeServiceImpl that implements the EmployeeService interface.
   • Create a property employeeRepository of type EmployeeRepository.
   • Initialize the employeeRepository property in a no-arg constructor.
   • Override all the abstract methods with appropriate logic.

5. Test Implementation:

   • In CollectionTest.java, create an instance of EmployeeServiceImpl and test all the methods by passing the appropriate data.

---

This README provides an overview of exercises focused on Java 8 features, specifically Lambda Expressions, Streams, and the Optional Class. Follow the tasks to implement the required functionality and ensure proper exception handling and data processing.